Robot Re-localization Package for |ros| Navigation
===================================================

The Robot Re-localization package empowers |ros| navigation with the capability to re-localize a robot. In situations where sensor measurements encounter glitches or environment disturbances or scene similarities lead to localization loss, the robot may lose its position. This necessitates a fast and reliable re-localization algorithm to re-establish the robot's location accurately. To tackle this issue, we developed an innovative re-localization algorithm that excels in both computational efficiency and memory usage, specifically designed for mobile robots.

Getting Started
----------------

|p_amr| provides a |ros| |deb_pack| for the application, supported by the following platform:

- ROS version: humble

Install |deb_pack|
^^^^^^^^^^^^^^^^^^^^^^

Install the ``ros-humble-its-relocalization-bringup`` |deb_pack| from the |intel| |p_amr| APT repository

    .. code-block:: bash

       sudo apt install ros-humble-its-relocalization-bringup

Run the Re-localization
^^^^^^^^^^^^^^^^^^^^^^^

Run the following script to set environment variables and bring up |ros| navigation, and |tb3| robot in |Gazebo| simulation:

    .. code-block:: bash

       source /opt/ros/humble/setup.bash
       export TURTLEBOT3_MODEL=waffle_pi
       export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:/opt/ros/humble/share/turtlebot3_gazebo/models
       ros2 launch nav2_bringup tb3_simulation_launch.py headless:=False

Set the robot **2D Pose Estimate** in rviz2:

    #. Set the initial robot pose by pressing **2D Pose Estimate** in rviz2.

    #. At the robot estimated location, down-click inside the 2D map. For
        reference, use the robot pose as it appears in Gazebo*.

    #. Set the orientation by dragging forward from the down-click. This also
        enables |ros| navigation.

      .. image:: ../../../images//2d_pose_estimate.png

Once |ros| navigation is running in Gazebo and the initial robot position is set, open a new terminal to bring up the re-localization:

    .. code-block:: bash

       source /opt/ros/humble/setup.bash
       ros2 launch relocalization_bringup relocalization.launch.xml 

To simulate the re-localization package, we have developed a demo application that replicates a scenario in which the sensor encounters a temporary failure. In this application, the sensor is disabled for a few seconds while the robot is traveling towards its goal. Once the sensor measurements are re-enabled, the robot will automatically re-localize itself and resume its navigation toward the goal. To run this demo application execute:

    .. code-block:: bash

       ros2 launch relocalization_bringup relocalization_demo.launch.xml mode:=demo

   .. note::

      Before launching the relocalization package, ensure that the robot initial pose has been set as described above.

Troubleshooting
---------------


For general robot issues, go to :doc:`../../../dev_guide/tutorials_amr/robot-tutorials-troubleshooting`.